/*
 * This is eMonocot, a global online biodiversity information resource.
 *
 * Copyright © 2011–2015 The Board of Trustees of the Royal Botanic Gardens, Kew and The University of Oxford
 *
 * eMonocot is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * eMonocot is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * The complete text of the GNU Affero General Public License is in the source repository as the file
 * ‘COPYING’.  It is also available from <http://www.gnu.org/licenses/>.
 */
package org.emonocot.harvest.common;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipException;
import java.util.zip.ZipOutputStream;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.batch.core.ExitStatus;

/**
 * @author jk
 *
 */
public class FileResourceZipper {

	/**
	 *
	 */
	private static final int BUFFER_SIZE = 1024;

	/**
	 *
	 */
	private static Logger logger = LoggerFactory.getLogger(FileResourceZipper.class);

	/**
	 * @param source The file or directory of files to write to the zip file
	 * @param target The absolute filepath for the zip file to be written
	 * @throws IOException
	 */
	public static final void zip(final String source, final String target) throws IOException, ZipException {
		ZipOutputStream zipOutputStream = null;
		File sourceFile = null;
		//Either source or array of files if the source is a directory
		String[] filenames = null;

		try { //to wrap things we can de-reference immediately
			sourceFile = new File(source);
			if(!sourceFile.exists()) {
				throw new FileNotFoundException("Unable to find filesystem resource - " + source);
			}
			if(sourceFile.isDirectory()) {
				filenames = sourceFile.list();
			} else {
				filenames = new String[] {source};
			}

			FileOutputStream fileOut = new FileOutputStream(target);
			BufferedOutputStream bufferedOut = new BufferedOutputStream(fileOut, BUFFER_SIZE);
			zipOutputStream = new ZipOutputStream(bufferedOut);
		} catch (IOException e) {
			logger.error("Unable to initalise files for writing " + source + " to " + target, e);
			throw e;
		}

		try {
			byte[] buffer = new byte[BUFFER_SIZE];

			logger.debug("Attempting to add " + filenames.length + " file(s) to zip");
			for (String filename : filenames){
				FileInputStream fileIn = null;
				if (source.endsWith("/")) {
					fileIn = new FileInputStream(source + filename);
				} else if (source.equals(filename)){
					fileIn = new FileInputStream(filename);
				} else {
					fileIn = new FileInputStream(source + "/" + filename);
				}
				zipOutputStream.putNextEntry(new ZipEntry(filename));
				int length;
				while ((length = fileIn.read(buffer)) != -1) {
					zipOutputStream.write(buffer, 0, length);
				}
				fileIn.close();
			}
		} catch (IOException e) {
			logger.error("Error writing " + source + " to " + target, e);
			throw e;
		} finally {
			try {
				zipOutputStream.close();
			} catch (IOException e) {
				logger.error("Unable to close ZipOutputStream " + zipOutputStream, e);
				throw e;
			}
		}
	}

	/**
	 * @param source The directory containing the DwC/A files
	 * @param target The absolute filepath for where to write the archive
	 * @return
	 */
	public static final ExitStatus packArchive(final String source, final String target) {

		logger.info("Attempting to pack " + source + " to " +  target);
		try { //to wrap things we can de-reference immediately
			File sourceDir = new File(source);
			if(!sourceDir.exists()) {
				throw new FileNotFoundException("Unable to find filesystem resource - " + source);
			}
			if(!sourceDir.isDirectory()) {
				throw new IllegalArgumentException(source + " is not a folder");
			}

			zip(source, target);
			return ExitStatus.COMPLETED;
		} catch (Exception e) {
			logger.error("Error writing " + source + " to " + target, e);
			return ExitStatus.FAILED;
		}
	}

}